Initial release — OpenMontage: the first open-source agentic video production system
11 production pipelines, 47 tools, 124 agent skills. Supports cloud APIs (fal.ai, OpenAI, ElevenLabs, Suno, HeyGen, Runway) and free local providers (diffusers, Piper TTS, WAN 2.1, Hunyuan, CogVideo). Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
This commit is contained in:
calesthio
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---
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name: video-edit
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description: |
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Edit videos locally using ffmpeg. Trim, concat, resize, speed, overlay, extract audio, compress, and convert.
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Use when: (1) Trimming or cutting video segments, (2) Concatenating multiple clips, (3) Resizing video for social platforms,
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(4) Extracting or replacing audio, (5) Compressing video, (6) Converting video formats, (7) Getting video info.
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---
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# Video Edit
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Edit videos locally by running ffmpeg/ffprobe directly. No wrapper scripts needed.
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## Prerequisites
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Install ffmpeg (includes ffprobe):
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```bash
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# macOS
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brew install ffmpeg
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# Ubuntu/Debian
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sudo apt update && sudo apt install -y ffmpeg
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# Verify
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ffmpeg -version && ffprobe -version
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```
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## Quick Reference
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### Get video info
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```bash
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ffprobe -v quiet -print_format json -show_format -show_streams video.mp4
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```
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### Trim
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```bash
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ffmpeg -y -ss 00:00:30 -to 00:01:45 -i video.mp4 -c copy trimmed.mp4
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```
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### Concatenate clips
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```bash
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# 1. Create a file list
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printf "file '%s'\n" clip1.mp4 clip2.mp4 clip3.mp4 > list.txt
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# 2. Concat with stream copy
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ffmpeg -y -f concat -safe 0 -i list.txt -c copy joined.mp4
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```
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### Resize for platform
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```bash
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ffmpeg -y -i video.mp4 \
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-vf "scale=1080:1920:force_original_aspect_ratio=decrease,pad=1080:1920:(ow-iw)/2:(oh-ih)/2:black" \
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-c:a copy tiktok.mp4
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```
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### Change speed
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```bash
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# 2x faster
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ffmpeg -y -i video.mp4 -filter:v "setpts=0.5*PTS" -filter:a "atempo=2.0" fast.mp4
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# 0.5x (slow motion)
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ffmpeg -y -i video.mp4 -filter:v "setpts=2.0*PTS" -filter:a "atempo=0.5" slow.mp4
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```
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### Extract audio
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```bash
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ffmpeg -y -i video.mp4 -vn -acodec libmp3lame audio.mp3
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```
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### Replace audio
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```bash
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ffmpeg -y -i video.mp4 -i audio.mp3 -c:v copy -map 0:v:0 -map 1:a:0 -shortest output.mp4
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```
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### Compress
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```bash
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ffmpeg -y -i video.mp4 -crf 23 -preset medium -c:a copy compressed.mp4
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```
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### Convert format
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```bash
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ffmpeg -y -i video.mov output.mp4
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```
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### Add image overlay
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```bash
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# Logo in top-right corner
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ffmpeg -y -i video.mp4 -i logo.png \
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-filter_complex "overlay=W-w-10:10" -c:a copy watermarked.mp4
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```
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## Platform Presets
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| Platform | Resolution | Scale + pad filter |
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|------------|-------------|-------------------------------------------------------------------------------------------------------|
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| TikTok | 1080 x 1920 | `scale=1080:1920:force_original_aspect_ratio=decrease,pad=1080:1920:(ow-iw)/2:(oh-ih)/2:black` |
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| YouTube | 1920 x 1080 | `scale=1920:1080:force_original_aspect_ratio=decrease,pad=1920:1080:(ow-iw)/2:(oh-ih)/2:black` |
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| Instagram | 1080 x 1350 | `scale=1080:1350:force_original_aspect_ratio=decrease,pad=1080:1350:(ow-iw)/2:(oh-ih)/2:black` |
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| Square | 1080 x 1080 | `scale=1080:1080:force_original_aspect_ratio=decrease,pad=1080:1080:(ow-iw)/2:(oh-ih)/2:black` |
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| Twitter/X | 1920 x 1080 | `scale=1920:1080:force_original_aspect_ratio=decrease,pad=1920:1080:(ow-iw)/2:(oh-ih)/2:black` |
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Use the filter with: `ffmpeg -y -i input.mp4 -vf "<filter>" -c:a copy output.mp4`
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## Tips
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- Always use `-y` to overwrite output without prompting.
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- Use `-c copy` when you only need to cut/join (no re-encoding, very fast).
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- Lower CRF = better quality, larger file. Range 18-28 is typical; 23 is the default.
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- For detailed recipes and flag explanations, see `references/operations.md`.
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# Operations Reference
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Detailed ffmpeg recipes for every operation. Each section shows the command, explains key flags, and lists common variations.
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---
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## info
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Get full metadata about a video file using ffprobe.
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```bash
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ffprobe -v quiet -print_format json -show_format -show_streams video.mp4
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```
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**Key flags:**
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- `-v quiet` — suppress banner/log noise, output only the requested data.
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- `-print_format json` — output as JSON (easy to parse). Also accepts `csv`, `flat`, `ini`.
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- `-show_format` — container-level info: duration, bitrate, format name, size.
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- `-show_streams` — per-stream info: codec, resolution, frame rate, sample rate, channels.
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**Variations:**
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```bash
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# Duration only (seconds, as plain text)
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ffprobe -v error -show_entries format=duration -of default=noprint_wrappers=1:nokey=1 video.mp4
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# Resolution only
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ffprobe -v error -select_streams v:0 -show_entries stream=width,height -of csv=s=x:p=0 video.mp4
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```
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---
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## trim
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Cut a segment from a video using stream copy (no re-encoding, very fast).
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```bash
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ffmpeg -y -ss 00:00:30 -to 00:01:45 -i video.mp4 -c copy trimmed.mp4
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```
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**Key flags:**
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- `-ss <time>` — seek to start position. Placed before `-i` for fast input seeking.
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- `-to <time>` — stop at this timestamp (absolute). Alternative: `-t <duration>` for relative duration.
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- `-c copy` — copy streams without re-encoding. Fast but cuts only on keyframes (may be off by a few frames).
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**Timestamps** accept `HH:MM:SS`, `HH:MM:SS.mmm`, `MM:SS`, or raw seconds (`90`, `90.5`).
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**Variations:**
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```bash
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# By duration instead of end time
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ffmpeg -y -ss 00:00:30 -t 75 -i video.mp4 -c copy trimmed.mp4
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# Frame-accurate trim (re-encodes, slower but exact)
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ffmpeg -y -ss 00:00:30 -to 00:01:45 -i video.mp4 -c:v libx264 -c:a aac trimmed.mp4
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```
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---
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## concat
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Join multiple video files into a single file.
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```bash
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# Step 1: Create a concat list file
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printf "file '%s'\n" clip1.mp4 clip2.mp4 clip3.mp4 > list.txt
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# Step 2: Concat with stream copy
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ffmpeg -y -f concat -safe 0 -i list.txt -c copy joined.mp4
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```
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**Key flags:**
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- `-f concat` — use the concat demuxer.
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- `-safe 0` — allow absolute paths in the file list.
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- `-c copy` — copy streams without re-encoding. Requires all inputs to share the same codec, resolution, and frame rate.
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**Variations:**
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```bash
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# Re-encode to normalize mismatched clips (slower)
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ffmpeg -y -f concat -safe 0 -i list.txt -c:v libx264 -c:a aac joined.mp4
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# Inline concat without a file (only for same-format files)
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ffmpeg -y -i "concat:part1.ts|part2.ts" -c copy joined.ts
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```
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---
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## resize
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Resize a video to specific dimensions with aspect-ratio-preserving padding.
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```bash
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ffmpeg -y -i video.mp4 \
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-vf "scale=1080:1920:force_original_aspect_ratio=decrease,pad=1080:1920:(ow-iw)/2:(oh-ih)/2:black" \
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-c:a copy resized.mp4
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```
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**Key flags:**
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- `-vf` — video filter chain.
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- `scale=W:H:force_original_aspect_ratio=decrease` — scale down to fit within WxH, preserving aspect ratio.
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- `pad=W:H:(ow-iw)/2:(oh-ih)/2:black` — pad to exact WxH with centered black bars.
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- `-c:a copy` — copy audio without re-encoding.
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**Variations:**
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```bash
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# Scale to width, auto-calculate height (maintains aspect ratio)
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ffmpeg -y -i video.mp4 -vf "scale=1280:-2" -c:a copy resized.mp4
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# Scale to height, auto-calculate width
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ffmpeg -y -i video.mp4 -vf "scale=-2:720" -c:a copy resized.mp4
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# Custom dimensions without padding (stretches)
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ffmpeg -y -i video.mp4 -vf "scale=1280:720" -c:a copy resized.mp4
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```
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---
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## speed
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Change playback speed of both video and audio.
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```bash
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# 2x faster
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ffmpeg -y -i video.mp4 -filter:v "setpts=0.5*PTS" -filter:a "atempo=2.0" fast.mp4
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# Half speed (slow motion)
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ffmpeg -y -i video.mp4 -filter:v "setpts=2.0*PTS" -filter:a "atempo=0.5" slow.mp4
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```
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**Key flags:**
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- `-filter:v "setpts=N*PTS"` — multiply presentation timestamps. `0.5` = 2x faster, `2.0` = half speed. Formula: `N = 1 / speed_factor`.
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- `-filter:a "atempo=F"` — adjust audio speed. Preserves pitch. Only supports values between 0.5 and 2.0.
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**For factors outside 0.5-2.0**, chain multiple atempo filters:
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```bash
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# 4x faster
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ffmpeg -y -i video.mp4 -filter:v "setpts=0.25*PTS" -filter:a "atempo=2.0,atempo=2.0" fast4x.mp4
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# 0.25x (very slow)
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ffmpeg -y -i video.mp4 -filter:v "setpts=4.0*PTS" -filter:a "atempo=0.5,atempo=0.5" slow025x.mp4
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```
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---
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## extract-audio
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Extract the audio track from a video file.
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```bash
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ffmpeg -y -i video.mp4 -vn -acodec libmp3lame audio.mp3
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```
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**Key flags:**
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- `-vn` — disable video (audio only output).
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- `-acodec <codec>` — audio codec to use.
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**Audio codec map:**
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| Format | Codec flag |
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|--------|------------------|
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| mp3 | `libmp3lame` |
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| wav | `pcm_s16le` |
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| aac | `aac` |
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| flac | `flac` |
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**Variations:**
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```bash
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# Extract as WAV (lossless)
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ffmpeg -y -i video.mp4 -vn -acodec pcm_s16le audio.wav
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# Extract as AAC
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ffmpeg -y -i video.mp4 -vn -acodec aac audio.aac
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# Copy audio codec as-is (fastest, keeps original format)
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ffmpeg -y -i video.mp4 -vn -acodec copy audio.aac
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```
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---
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## replace-audio
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Replace a video's audio track with a different audio file.
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```bash
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ffmpeg -y -i video.mp4 -i audio.mp3 -c:v copy -map 0:v:0 -map 1:a:0 -shortest output.mp4
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```
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**Key flags:**
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- `-i video.mp4 -i audio.mp3` — two inputs: video (index 0) and audio (index 1).
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- `-c:v copy` — copy video stream without re-encoding.
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- `-map 0:v:0` — take video from the first input.
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- `-map 1:a:0` — take audio from the second input.
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- `-shortest` — stop when the shorter input ends.
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**Variations:**
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```bash
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# Remove audio entirely (silent video)
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ffmpeg -y -i video.mp4 -c:v copy -an silent.mp4
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# Mix original audio with new audio (overlay, not replace)
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ffmpeg -y -i video.mp4 -i music.mp3 \
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-filter_complex "[0:a][1:a]amix=inputs=2:duration=first[a]" \
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-map 0:v -map "[a]" -c:v copy mixed.mp4
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```
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---
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## overlay
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Add an image overlay (watermark, logo) on top of a video.
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```bash
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# Bottom-right corner (10px padding)
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ffmpeg -y -i video.mp4 -i logo.png \
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-filter_complex "overlay=W-w-10:H-h-10" -c:a copy watermarked.mp4
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```
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**Key flags:**
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- `-filter_complex "overlay=X:Y"` — position the overlay image at coordinates X,Y.
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- `-c:a copy` — copy audio without re-encoding.
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**Position expressions:**
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| Position | Expression |
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|--------------|-------------------------|
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| Top-left | `overlay=10:10` |
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| Top-right | `overlay=W-w-10:10` |
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| Bottom-left | `overlay=10:H-h-10` |
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| Bottom-right | `overlay=W-w-10:H-h-10` |
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| Center | `overlay=(W-w)/2:(H-h)/2` |
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`W`/`H` = video dimensions, `w`/`h` = overlay image dimensions.
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**Variations:**
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```bash
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# With opacity (semi-transparent watermark)
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ffmpeg -y -i video.mp4 -i logo.png \
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-filter_complex "[1:v]format=rgba,colorchannelmixer=aa=0.5[ovr];[0:v][ovr]overlay=W-w-10:10" \
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-c:a copy watermarked.mp4
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# Overlay only during a time range (show from 5s to 15s)
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ffmpeg -y -i video.mp4 -i logo.png \
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-filter_complex "overlay=10:10:enable='between(t,5,15)'" -c:a copy watermarked.mp4
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```
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---
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## compress
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Reduce video file size.
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### CRF-based (simple, recommended)
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```bash
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ffmpeg -y -i video.mp4 -crf 23 -preset medium -c:a copy compressed.mp4
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```
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**Key flags:**
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- `-crf <int>` — Constant Rate Factor. Lower = better quality, larger file. 0 = lossless, 18 = visually lossless, 23 = default, 28 = smaller/lower quality.
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- `-preset <speed>` — encoding speed/compression tradeoff: `ultrafast`, `superfast`, `veryfast`, `faster`, `fast`, `medium`, `slow`, `slower`, `veryslow`. Slower = smaller file at same quality.
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- `-c:a copy` — copy audio as-is.
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### Target file size
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To hit a specific file size, calculate the required video bitrate:
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```bash
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# Formula: video_bitrate = (target_MB * 8 * 1024) / duration_seconds - audio_bitrate
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# Example: 25MB target, 120s video, 128kbps audio
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# video_bitrate = (25 * 8 * 1024) / 120 - 128 = 1578 kbps
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ffmpeg -y -i video.mp4 \
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-b:v 1578k -maxrate 1578k -bufsize 3156k \
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-c:a aac -b:a 128k \
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compressed.mp4
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```
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**Variations:**
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```bash
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# Aggressive compression (smaller, lower quality)
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ffmpeg -y -i video.mp4 -crf 28 -preset slow -c:a copy small.mp4
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# High quality (larger file)
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ffmpeg -y -i video.mp4 -crf 18 -preset slow -c:a copy hq.mp4
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```
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---
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## convert
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Convert a video to a different container format.
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```bash
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ffmpeg -y -i video.mov output.mp4
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```
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ffmpeg infers the output format from the file extension. For most conversions, this is all you need.
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**Supported formats:** mp4, mov, avi, mkv, webm, gif.
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### GIF conversion (high quality, two-pass palette)
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```bash
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# Step 1: Generate optimized palette
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ffmpeg -y -i video.mp4 -vf "fps=15,scale=480:-1:flags=lanczos,palettegen" palette.png
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# Step 2: Use palette for high-quality GIF
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ffmpeg -y -i video.mp4 -i palette.png \
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-filter_complex "fps=15,scale=480:-1:flags=lanczos[x];[x][1:v]paletteuse" output.gif
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# Clean up
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rm palette.png
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```
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**Variations:**
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```bash
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# Quick GIF (lower quality, single pass)
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ffmpeg -y -i video.mp4 -vf "fps=10,scale=320:-1" output.gif
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# Convert to WebM (VP9)
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ffmpeg -y -i video.mp4 -c:v libvpx-vp9 -crf 30 -b:v 0 -c:a libopus output.webm
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```
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Reference in New Issue
Block a user